Asynchronous Massive MIMO Base Station Cooperation for 5 G Networks and Beyond

该研究提案名为“5G网络及未来的异步大规模MIMO基站协作”，旨在研究配备大量天线（即支持大规模MIMO）的基站之间的分布式协作方案，以实现多个用户对之间的同时通信（多个点对点通信）。尽管这种多用户场景具有实际重要性，但文献中尚未对其进行研究。如果考虑到由于用户的物理位置的差异而导致多个用户以时间异步的方式进行操作，则这种场景的实际重要性将进一步凸显。事实上，在这项研究中，网络被假设为时间异步的，这意味着一个用户传输的信号会经历不同的延迟才能到达网络中的基站。此外，不同基站发送的信号对于特定用户来说经历不同的延迟。由于用户链路的这种现实模型，端到端用户信道只能建模为多抽头频率选择性链路，因此需要对网络进行宽带考虑、设计和分析，而现有文献则侧重于窄带（单载波）方案。

Titled as "Asynchronous Massive MIMO Base Station Cooperation for 5 G Networks and Beyond", this research proposal aims to study distributed cooperation schemes among base-stations, which are equipped with a large number of antennas (i.e., to support massive MIMO), to enable simultaneous communications between multiple user pairs (multiple peer-to-peer communications). Such a multi-user scenario has not been studied in the literature, despite its practical importance. The practical importance of such scenarios is further highlighted if one takes into account that the multiple users operate in a time-asynchronous manner induced by the difference in the physical locations of the users. Indeed, in this study, the network is assumed to be time-asynchronous, meaning that the signal transmitted by one user undergoes different delays to reach the base stations in the network. Furthermore, the signals transmitted by different base stations undergo different delays to a particular user. Due to this realistic model for the user links, the end-to-end user channels can be modeled only as multi-tap frequency selective links thereby requiring wideband consideration, design, and analysis of the network, while the available literature focuses on narrowband (single-carrier) schemes.